Richard, from a scientific viewpoint the global average temperature is very indirect evidence. This average is a sophisticated amalgamation of local observations and working out what it actually was in the past is doubly difficult. It is always going to have a degree of uncertainty to it and be open to revision. I would liken it to assessing all the gold reserves, say, in the world. To be sure of getting it right you have to be determined to drill holes in less and less accessible places and to a finer and finer scale and once you have done it, what does it actually prove? It satisfies your critics, may be?

What gives me certainty is the bigger picture. Look at the temp of the moon; compare it to the Earth’s. Why is there a difference? Compare Earth to Venus? Why is there a difference? Here’s an interesting figure for you, and it doesn’t matter whether it’s up or down a bit: current global annual consumption of oil: one cubic mile. Try to imagine that, a huge tank rising into the clouds and much of it being turned into CO2 which is measured in part per million! (and this figure does not include coal, etc)

The greenhouse gases with their absorption bands are the only game in town from my perspective. Don’t be distracted by the bulls*it on the internet! Isn’t that what you are saying is the modern problem?

As they say, statistics lie: don’t trust them. Statistical types love playing with them. Fair enough, theories in areas like economics will (may be) never be good enough, so you need statistics as a back up and to keep you honest. But it seems to me that the people at places like climateaudit live in their own little world. They’re trying to work out if someone’s cooking the books by looking at the shadow of the smoke. If you are into conspiracy theories, that’s your bag. I don’t buy it. Sorry, out of time and word limit

Let's go over the real issues sofar, because Richard Castles is muddying the waters and I'm not interested in that.

Castles writes an article about the mild weather of Canberra and the 42 degree heatwave which occurred in 1968. This is used to suggest that climate change has somehow missed Canberra and who knows the future. Global warming is an Internet "virus", suggests Castles. We can see some posters have taken up these suggestions.

But the glaring and inexcusable omission is that the Bureau of Meterology has said that 2006 was the hottest Canberra year on record. One can look at the other BOM weather summaries over the past few years and can see other reports on the increasingly warm weather in the nations capital. (See http://www.bom.gov.au/climate/current/annual/act/summary.shtml)

Since presenting the BOM view on Canberra's weather, Castles has made three posts (28/2, 1/3 and 7/3) which do everything but explain the glaring disparity between his anecodotal article and the BOM report based on 60 plus years of readings.

Did Castles fail to research his article properly?

Does Castles dispute the BOM and other scientific reports?

Does Castles still believe that there is no evidence for a warmer Canberra?

We do not know these answers because it is necessary for a global warming skeptic to give a obtuse or political reponse for them to hold onto their outdated views. That is the internal psychological mechanism for those too embarassed to find that they were wrong.

This is a great shame, as for anyone who is concerned for their children or grandchildren, one would think this would override any personal intertia to review their position. The above series of posts from Richard Castles is an example of this not happening.

David Latimer: "We do not know these answers..."

Well, not through lack of trying.

SoS, thank you for your comments, but I’m afraid you’ve lost me.

First you say: “The democratising effect of the internet, for better or worse, gives weight and distribution to views which would not previously have got that treatment.” Then: “Don’t be distracted by the bulls*it on the internet!”

You say statistics lie, but then that you need them “as a back up and to keep you honest.”

I concede I may have misunderstood you - There can be a lot of 'noise' in the simplest communication - but it seems that the skeptical loop suggested by your nom de plume is getting you tangled.

You seem to concur that there is a degree of uncertainty in even the basic measurements. Surely, the statistical “types” you talk of should be there to dispassionately keep an eye out for cases where statistics are being misused, especially to assert a degree of certainty that doesn’t exist.

Finally, how is the difference between the earth and the moon, relevant to changes on earth over time?

"How is the difference between the earth and the moon, relevant to changes on earth over time?" (Posted by Richard Castles)- "How is the difference between the earth and the moon, relevant to changes on earth over time?" (Posted by Richard Castles)- So far as I remember, planetary forces reflect planets' masses-in-square ratio while altering of geo-magnetic characteristics affects no grand mass of the Earth eventually.

Therefore, difference between Moon and Earth is stable from a cosmic view

Richard, sorry if I confused. We seem to come from different perspectives. I assumed that you’d understand how Venus and Moon fit in this: one exhibiting a runaway greenhouse effect, the other a complete lack thereof. I wonder about your scientific background and therefore the basis for your strong opinion on this subject.

I am basically saying that the theoretical underpinning of AGW is very strong. If the earth were moon-like in atmosphere it would have an average temperature of about minus 17 degrees Celsius. Its actual temperature is some thirty degrees warmer. It is long- established that the only explanation for this is the natural greenhouse effect. This being so, a naïve thinker should opine that 30% increase of the GHGs, as at present, would result in a 10 degree temperature increase. That should be the position of an unscientific person skeptical of modern science, models, etc. He should be asking how come the present warming is so small, not the other way around, as the alleged “skeptics” do.

As the big picture of the strength of the greenhouse effect, which is backed by lab measurements of gas absorption bands, etc, etc, is so strong, the scientists are not going to be deflected by highly derivative figures like global average temperatures which are of necessity noisy and hard to pin down. What are climateaudit trying to do? Find that the warming trend has been 0.4 instead of 0.6 degrees? Prove the scientists are hiding an inconvenient truth? They are basically a small, less-deluded-than-average subset of conspiracy theorists. The scientists would be quite happy if the figure were lower and we had more time to fight the problem. However, given the strength of the theory, they are more likely just to worry about the source of the error.

It’s your thesis that fear of AGW is bred on the internet. My counter-theory is that conspiracy theorists like climateaudit are muddying the waters and damping down public reaction to a legitimate public concern

SoS, I am aware of the greenhouse effect. I understand Venus's "runaway" effect begins with the fact that it is closer to the sun. I would indeed question why current warming is so small, given that "the theoretical underpinning of AGW is very strong" and "the big picture of the strength of the greenhouse effect...is so strong". Suggests some gaps in our knowledge.